PI (Profibus and Profinet International) is the latest organisation to adopt the IEEE’s TSN (Time-Sensitive Networking) technology, which combines the bandwidth of IT (information technology) networks with the latency of OT (operational technology) networks.

At the Hannover Fair, PI announced that its Industry 4.0 working group has worked out the requirements and goals for the future use of TSN in Profinet. The focus will be on making it easy for Profinet users to apply the new technology in their devices and systems. Services such as diagnosis and parameterisation will stay the same, and network configuration will be performed in the familiar way. PI says this will allow “an easy transition to the new Ethernet landscape” and will ensure broad acceptance among Profinet users.

“PI will expand Profinet with the mechanisms of TSN in layer 2, retaining the application layer on the higher levels,” PI chairman, Karsten Schneider, explained at Hannover. “This makes it possible to migrate the applications to the new technology simply and incrementally and to take advantage of the advantages of an open, globally standardised IT technology.”

PI says that because Profinet uses standard Ethernet technology, it can draw on a broad range of Ethernet chips for implementing Profinet interfaces on devices, as well as benefiting from aspects of the IEEE technology, such as gigabit bandwidths.

TSN will allow synchronous networks to be implemented for isochronous applications. Previously, networks had to be set up separately and integrated in dedicated chips in devices. PI says that this will ensure not only that Profinet remains future-proof, but also that simpler setups will be possible.

PI says that is adding TSM to the Profinet architecture in a way that is easy to integrate and scale

In addition to producing a stack architecture that is easy to integrate and scale, a further aim of adopting TSN is to bring a high degree of determinism and robustness to IP-based traffic that is not real-time capable. Because TSN allows bandwidth to be reserved on the network for individual tasks, so they are not disrupted by other traffic, reliability should improve. PI argues that this is especially important, because future Industry 4.0 networks will use a variety of protocols side-by-side. PI will offer, from the outset, parallel communication via OPC UA between stations at the system level, or from devices on the field level to the cloud.

With the introduction of TSN, it will also be necessary to simplify the engineering of networks for more complex systems, until they become plug-and-work-capable and allow reconfiguration during operation.